It sometimes occurs that the testicles, which in the early period of life are still in the belly (Plate XXXIV), fail to appear in the scrotum. For some reason or other connected with development, they are either retained in the abdominal cavity or stop short in the inguinal canal.
When this occurs such an animal is said to be a rig or ridgling, or more technically a cryptorchid. It is not uncommonly observed that one or both the testicles fail to descend in the sac. In the former case the horse is termed a monarchid, while in the latter he is distinguished as a double cryptorchid.
When the testicles do not "come down" into the scrotum the animal has all the attributes of a stallion, and he is consequently unable to be stabled with mares or turned to grass with other horses.
Horses in this condition are frequently capable of getting foals, are for the most part troublesome, and are undesirable property. Moreover, their progeny are liable to be afflicted with the same malformation as themselves; in other words the defect is congenital. It becomes necessary, therefore, that such animals should be castrated.
The operation to be resorted to is for the most part simple and free from danger, but where the testicles remain in the abdomen special care is needed for their removal.
In all cases it is desirable to prepare the horse for the operation by restricting his diet to bran and slops for two or three days; and, for twenty-four hours previously, withholding all kinds of food and restricting his water to half-rations.
This done, the horse is cast and fixed in the manner usually resorted to for castration. The operation is very much facilitated by the administration of an anaesthetic, when every muscle is relaxed and the animal lies quietly instead of struggling, as is the case where he is not under its influence.
Chloroform is undoubtedly the most useful agent in this connection, since it controls the entire body and deprives the horse of consciousness and feeling.
To empty the rectum before the operation .is also a desirable course to pursue, and the tail should be tied up, and after the administration of chloroform has taken place it may be carried forward out of the way and tied to the collar.
The instruments which will be needed are a castrating knife (fig. 516), artery forceps, a pair of dressing forceps, a needle, strong silk, silkworm gut, and an ecraseur (fig. 523).
Before commencing the operation it will be necessary that these several items be placed in a 5-percent solution of carbolic acid for forty-eight hours, otherwise they must be thoroughly boiled and kept in hot water until required Cotton-wool or sponges, whichever may be used, should be rendered sterile by the same treatment.
The hair in and about the scrotum must be removed by close clipping, and the site of the incision should be thoroughly washed with warm antiseptic water and soap. After washing, the part should be carefully soaked again and again with fresh antiseptic solution.
This should be done by the operator, whose hands will at the same time be undergoing disinfection. When complete, the part should be wiped thoroughly dry, and then the hands and arms of the operator must be washed and brushed with hot water and soap, and afterwards soaked for five minutes in fresh carbolic solution. Special attention should be given to the nails; in these cases they should always be cut short and be surgically clean.
The same treatment must apply to the assistant and anyone who may be told off to handle the instruments.
The first step in the operation is to make an incision carefully through the skin and the thin layer of elastic tissue beneath it, taking care to avoid cutting into any of the vessels forming the rich plexus of veins which are disseminated through the connective tissue beneath. This incision must be about 5 inches in length over the site of the testicle.
Fig. 528. - Dressing Forceps and Artery Forceps.
The subcutaneous connective tissue is then to be torn through and pushed aside with the fingers, until the outer ring of the inguinal canal is reached. Sometimes the testicle is found immediately within it, in which case it will be seized and removed by passing the ecraseur around the cord by which it is suspended. In other instances it is placed higher up in the canal, and in some cases it is found in the cavity of the belly. Whether it be found in the one place or the other it must be brought out, or the chain of the ecraseur must be carried to it and placed around the cord, and by slow but continuous turns of the screw divided. Should any difficulty arise in meeting with it in the abdomen, the hand should be passed to the upper surface of the bladder, where the vas deferens, a firm tube about two-thirds the diameter of a lead pencil, will be found, and this followed in a forward direction will lead to the testis.
When the abdomen is opened and the internal ring enlarged, there is of course some danger of escape of the intestines. This may be guarded against by suturing the skin closely with interrupted sutures of silkworm gut, and in some measure also by allowing the horse to rise from the ground while lying on the -side from which the testicle has been removed. This done, my friend Professor Hobday suggests that the skin be covered with iodoform and collodion (l to 10) or orthoform and collodion (l to 8).
From a consideration of the following table of cases operated upon by Professor Hobday, it will be seen that -
In 36 instances the right testicle alone was missing, whilst in 29 the left was the offending organ.
In 11 of the cases both testicles were concealed.
In 39 instances the organ was found in the abdomen, and in 43 it was in the inguinal canal.